This invention relates to the recovery of base metals from sulphide ores and concentrates.
Conventional processing of base metals sulphide ores includes flotation and pyrometallurgical techniques as smelting of concentrates.
U.S. Pat. No. 4,283,017 describes a selective flotation of cubanite and chalcopyrite from copper/nickel mineralized rock. The disadvantage of this process consists in the ore beneficiation process, which requires high energy consume in order to reach very fine particles. The present invention can be fed with coarse particles.
U.S. Pat. No. 3,919,079 describes a process of flotation of sulphide minerals from sulphide bearing ore. The disadvantage of this process consists in the flotation process which use complex reagents: Dispersant, Collector, Alkali, Floculants. The complex reagents used in the flotation can cause environmental impact due to chemical oxygen demand for the decomposition of these reagents. The present invention does not require complex reagents.
U.S. Pat. No. 5,281,252 describes a conversion of non-ferrous sulfides which requires the insufflation of the copper sulphide particles and this process requires a complex control of agitation levels and contact of solid/liquid. Further, it requires the control of the internal atmosphere to ensure the reduction of the copper and the power supply for the reaction.
U.S. Pat. No. 4,308,058 describes a process for the oxidation of molten low-iron metal matte to produce raw metal. This process, however, requires multiple furnace operations as well as high temperatures (>1000° C.) which involves high energy consumption.
However these conventional processes become very expensive when dealing with low grade material and ores with high impurities content like chlorine and fluorine. Another problem with pyrometallurgical processing is the high capital of costs of a new plant, environmental, issues and high energy consumption.
Usually, when dealing with low grade material and ores with high impurities content, the gases resulting (dust; CO2; NOx; H2O) from the process must be treated before sending the SO2 to a sulphuric acid plant. Alternative methods comprise burning the concentrate.